GMAT Quantitative Review
3.0 Math Review
3.2 Algebra
7. Exponents
A positive integer exponent of a number or a variable indicates a product, and the positive integer is the number of times that the number or variable is a factor in the product. For example, x5 means (x)(x)(x)(x)(x); that is, x is a factor in the product 5 times.
Some rules about exponents follow.
Let x and y be any positive numbers, and let r and s be any positive integers.
1. (1) 
; for example, 
.
2. (2) 
; for example, 
.
3. (3) 
; for example, 
.
4. (4) 
; for example, 
.
5. (5) 
; for example, 
.
6. (6) 
; for example, 
.
7. (7) 
; for example, 
.
8. (8) 
; for example, 
and 
.
It can be shown that rules 1–6 also apply when r and s are not integers and are not positive, that is, when r and s are any real numbers.